The players are in track clothes, take a track stance and run 40 yards. Do this even happen in a football game?

I see dudes in helmets and pads. They're standing or in three/four point positions. None are standing like a track star. There is a football in someone's hands. Finally, if a lineman is running 40 yards, he's way behind someone else. Does it matter if he's 30 steps or 32 steps behind them?